2947991 has 4 divisors (see below), whose sum is σ = 2989584. Its totient is φ = 2906400.

The previous prime is 2947949. The next prime is 2947999. The reversal of 2947991 is 1997492.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2947991 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2947999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20690 + ... + 20831.

It is an arithmetic number, because the mean of its divisors is an integer number (747396).

2^2947991 is an apocalyptic number.

2947991 is a deficient number, since it is larger than the sum of its proper divisors (41593).

2947991 is an equidigital number, since it uses as much as digits as its factorization.

2947991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41592.

The product of its digits is 40824, while the sum is 41.

The square root of 2947991 is about 1716.9714616149. The cubic root of 2947991 is about 143.3866498364.

The spelling of 2947991 in words is "two million, nine hundred forty-seven thousand, nine hundred ninety-one".